Field of the Invention
The invention relates in general to negative molds and in particular to a negative mold of two or more mold portions which are detachable from each other for the manufacture of shapes consisting of synthetic material for adapter blocks, used in particular in fluid technology. The negative mold encloses a mold chamber receiving the material to be molded into which at least one projection representing the negative for a surface depression to be produced in the adapter shape, for example a channel or a chamber or similar, projects with its mold insert which is arranged on one of the mold portions above its fastening shank which is inserted into an opening of the mold portion.
In the field of pneumatics pneumatic circuits are no longer produced through individual hose connections, which make clear overview difficult, but by using so-called adapter blocks. These have possibilities for connecting several pressure users and/or sources or similar, and they contain interior channels extending according to needed connections. For simplified manufacture of the interior channels the adapter blocks are customarily put together consisting of at least two structural parts which are glued together, of which at least one consists of a plastic and has in the region of the glued surface, depression covered by the other part. The depressions form the channels once they are glued. The manufacture of the adapter shapes having the surface depressions takes place, for example in a plastic injection molding process or by introducing a foamable material into the mold chamber and expanding by foaming and curing, forming a structured shape.
Such negative mold and a corresponding method are known from DEP 31 24 020. Here the inserts used for sparing the surface depressions are formed in the shape of cylindrical molding pins which are held in corresponding openings of the individual mold portions. It is of disadvantage here that during the casting, respectively foaming, process frequently a given quantity of the material to be cast, respectively foamed, in the region of the outer circumference of the insert penetrates into the opening of the particular mold portion receiving the shank. The material is deposited in the orifice region of the opening and forms a collar firmly connected with the manufactured adapter shape which cannot be removed even when the shape is removed from the negative mold. Consequently, after the casting, respectively foaming, process further processing steps are required to remove the cast collar respectively mold mark and to ensure in the subsequent finished state proper throughflow and, hence, proper functioning of the adapter block.